#!/usr/bin/env bash
factorial=1
for (( number = 1; number <= $1 ; number++ ))
do
      # $[ ] 代表基本运算需要这样写
      factorial=$[ $factorial * $number ]
   done
echo The factorial of $1 is $factorial

# 两个输入参数
total=$[ $1 * $2 ]
echo The first parameter is $1.
echo The second parameter is $2.
echo The total value is $total.